If convicted, Mohammed Morsi could face capital punishment. He already stands accused of a string of other charges, some of which also carry the death penalty, levelled as part of a crackdown on his Muslim Brotherhood group after the military deposed him last summer.

At Sunday's hearing, part of which was aired on state television, the prosecution accused Morsi and 35 other Brotherhood members of conspiring to destabilize the country and cooperating with foreign militant groups – including Palestinian Hamas and Lebanon's Hezbollah.

The case's chief prosecutor, Tamer el-Firgani, said Morsi, his aides and senior Brotherhood members had "handed over secrets to foreign countries, among them national defense secrets, and handed over a number of security reports to the Iranian Revolutionary Guard in order to destabilize the country's security and stability."

El-Firgani, divulging details of the charges, said national security reports meant for only Morsi to see were emailed to some of these foreign militant groups. One report, he said, was sent to the Iranians about the activities of Shiite Muslims in Egypt. Iran is mostly Shiite.

Morsi started off his time in office with repeated tirades against Iran over its support to Syrian President Bashar Assad, but soon warmed up to the Islamic Republic, allowing its tourists to come to Egypt for the first time in decades and founding a four-nation contact group on the Syrian war that included Iran.

Morsi and his co-defendants were present at the hearing without their defense team, which had walked out of the previous hearing in protest over the fact that the defendants were being held in a glass sound-proof cage. Defense lawyers appointed by the bar association were present in their place.

The cage was introduced after Morsi and his co-defendants interrupted the proceedings of other court cases by talking over the judge and chanting slogans. The cage is fitted to give the judge sole control over whether the defendants can be heard or not when speaking.

The military overthrew Morsi following millions-strong protests after just a year in power. Since his ouster, he has largely been kept out of the public eye, appearing only in carefully managed court sessions in which he has frequently shouted defiantly, insisting he is still Egypt's president.

The country's first freely elected president after autocratic ruler Hosni Mubarak was toppled in a popular uprising in February 2011, Morsi drew the ire of liberals, secular-leaning youth groups and a large sector of Egyptians who accused him and his Brotherhood of trying to monopolize power and failing to implement much-needed reforms.